Construction of lanthanide complexes supported by 2,3‐dimethoxybenzoic acid and 5,5’‐dimethy‐2,2’‐bipyridine: crystal structures, thermoanalysis, magnetic and fluorescence properties

Abstract

A series of novel trivalent lanthanide complexes, [Ln(2,3-DMOBA)3(5,5′-DM-2,2′-bipy)]2·C2H5OH (Ln = Eu(1), Sm(2), Gd(3), Ho(4) Er(5), Pr(6), Nd (7)) (2,3-DMOBA = 2,3-dimethoxybenzoate, 5,5′-DM-2,2′-bipy = 5,5′-dimethy-2,2′-bipyridine), have been successfully synthesized and structurally validated by single crystal diffraction. All complexes discussed herein feature a binuclear structure, and contain only one free ethanol molecule, which is interesting in the lanthanide complexes. The coordination number of center Ln3+ ions is nine, showing a distorted monocapped square anti-prismatic coordination geometry. Through a pair of alternating identical C-H···O hydrogen bonding interactions between two 2,3-DMOBA ligands on the same lanthanum binuclear unit with 5,5′-DM-2,2′-bipy ligands on two neighboring units, the binuclear complexes can form one-The thermal analysis of these complexes are investigated by TG-DSC/FTIR, the result show that the decomposition process of complexes are mainly divided into four stages with the formation of the respective oxides.The visible light emission experiment of complex 1 is carried out, and the characteristic luminescence behavior of intense red light is exhibited. What'more, fluorescence lifetimes as well as the fluorescent quantum yield of complex 1 is calculated. And the magnetic properties of complexes 3-5 are also studied.

Construction, Thermochemistry, and Fluorescence Properties of Novel Lanthanide Complexes Synthesized from Halogenated Aromatic Carboxylic Acids and Nitrogen-Containing Ligands

“…The measured peak pattern was in good agreement with the simulated peak pattern, indicating that the target complexes were synthesized with high purity 31 . Besides, the positions and peak shapes of the diffraction peaks of the same type of complex powder are the same, confirming that they have the same structure 32 . As a final note, the ligand powder peaks showed significant differences with respect to the complexes, indicating the formation of a new phase, not the result of mechanical summation of the ligand powders 31,32 .…”

Five Dinuclear Lanthanide Complexes Based on 2,4-dimethylbenzoic Acid and 5,5′-dimethy-2,2′-bipyridine: Crystal Structures, Thermal Behaviour and Luminescent Property

“…Among many organic ligands, aromatic carboxylic acid ligands are generally considered to be excellent organic ligands due to their ability to provide oxygen atoms and affinity for lanthanide cations ( Su et al, 2012 ). In addition, aromatic carboxylic acid ligands have multiple coordination sites, and oxygen atoms of carboxylic acid ligands can coordinate with lanthanide ions in various coordination modes, so lanthanide organic coordination complexes with various structures can be constructed ( Li et al, 2019 ). Most importantly, the introduction of aromatic carboxylic acid ligands can sensitize the fluorescence of lanthanide ions.…”